// by: 陈同学
#include<iostream>
using namespace std;
int main()
{
  void sort(int &x,int &y);
  cout<<"please enter two numbers:"<<endl;
  int a,b;
  cin>>a>>b;
  sort(a,b);
}
void sort(int &x,int &y)
{
  if(x>y) cout<<x<<" "<<y<<endl;
  else cout<<y<<" "<<x<<endl;
}